Transforms and assemblies

Transforms

node.transform(kind, params) moves a body or an assembly. It changes the node’s placement, not its shape.

Kind	Parameters
`OG_TRANSFORM_TRANSLATE`	`{ offset }`
`OG_TRANSFORM_ROTATE`	`{ axis, degrees, pivot? }`
`OG_TRANSFORM_SCALE`	`{ factor, pivot? }`
`OG_TRANSFORM_PLACE`	`{ origin?, xDirection?, normal?, scale? }`

Translate, rotate and scale add to the current placement. Place sets it.

import {
  OpenGeometry,
  Solid,
  OG_PRIMITIVE_CUBOID,
  OG_TRANSFORM_ROTATE,
  OG_TRANSFORM_TRANSLATE,
} from 'opengeometry';

await OpenGeometry.create(
  { wasmURL: '/opengeometry_bg.wasm' },
  { workerURL: '/tessellation-worker.js' },
);

const box = new Solid(OG_PRIMITIVE_CUBOID, { width: 1, height: 1, depth: 1 });
box.transform(OG_TRANSFORM_TRANSLATE, { offset: [2, 0, 0] });
box.transform(OG_TRANSFORM_ROTATE, { axis: [0, 1, 0], degrees: 90, pivot: [2, 0, 0] });
console.log(box.getPlacement());

getPlacement() returns { origin, xDirection, normal, scale } relative to the parent. getWorldPlacement() returns it in the world. Do not set position, rotation or scale on a body. The kernel puts the placement back and sends a PlacementOverwritten warning. A negative scale throws InvalidTransform. Use mirror.

Assemblies

A SystemAssembly groups nodes. Its children follow its placement.

import {
  OpenGeometry,
  Solid,
  SystemAssembly,
  OG_PRIMITIVE_CUBOID,
  OG_TRANSFORM_TRANSLATE,
} from 'opengeometry';

await OpenGeometry.create(
  { wasmURL: '/opengeometry_bg.wasm' },
  { workerURL: '/tessellation-worker.js' },
);

const desk = new SystemAssembly({ ogId: 'desk' });
const top = new Solid(
  OG_PRIMITIVE_CUBOID,
  { width: 1.6, height: 0.04, depth: 0.8 },
  { parent: desk },
);
const leg = new Solid(OG_PRIMITIVE_CUBOID, { width: 0.05, height: 0.71, depth: 0.05 });
desk.addChild([leg]);
top.transform(OG_TRANSFORM_TRANSLATE, { offset: [0, 0.71, 0] });
desk.transform(OG_TRANSFORM_TRANSLATE, { offset: [3, 0, 0] });
console.log(desk.getChildren(), desk.getBounds());

Pass parent in the options, or call addChild(children, { keepWorld? }).
removeChild(child, { keepWorld? }) takes a node out. With keepWorld: true the node keeps its world position; otherwise it keeps its local placement.
getChildren() returns the children’s ogId values. getParent() returns the parent’s ogId, or null.
Bodies have the same tree methods, so a body can be the parent of another body.
A SystemAssembly is not a Three.js object. Add its bodies to the scene yourself.
assembly.dispose() disposes the assembly.

Copies and instances

Call	Shape	Use it for
`body.duplicate({ ogId?, parent? })`	Own copy	A body that you will edit on its own
`body.instance({ ogId?, parent? })`	Shared	Many copies of one part, such as chairs

import { OpenGeometry, Solid, OG_PRIMITIVE_CUBOID, OG_TRANSFORM_TRANSLATE } from 'opengeometry';

await OpenGeometry.create(
  { wasmURL: '/opengeometry_bg.wasm' },
  { workerURL: '/tessellation-worker.js' },
);

const chair = new Solid(OG_PRIMITIVE_CUBOID, { width: 0.5, height: 0.9, depth: 0.5 });
const second = chair.instance();
second.transform(OG_TRANSFORM_TRANSLATE, { offset: [1, 0, 0] });
chair.rebuild(OG_PRIMITIVE_CUBOID, { width: 0.55, height: 0.9, depth: 0.5 }, { instances: 'all' });
console.log(chair.getInstanceCount(), second.getBounds());

An instance has its own placement and shares the shape. An edit of a shared shape needs { instances: 'all' }, or makeUnique() on the body that should change alone.

​Transforms

​Assemblies

​Copies and instances

Transforms

Assemblies

Copies and instances